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Author Esquivel-Muelbert, A.; Phillips, O.L.; Brienen, R.J.W.; Fauset, S.; Sullivan, M.J.P.; Baker, T.R.; Chao, K.-J.; Feldpausch, T.R.; Gloor, E.; Higuchi, N.; Houwing-Duistermaat, J.; Lloyd, J.; Liu, H.; Malhi, Y.; Marimon, B.; Marimon Junior, B.H.; Monteagudo-Mendoza, A.; Poorter, L.; Silveira, M.; Torre, E.V.; Dávila, E.A.; del Aguila Pasquel, J.; Almeida, E.; Loayza, P.A.; Andrade, A.; Aragão, L.E.O.C.; Araujo-Murakami, A.; Arets, E.; Arroyo, L.; Aymard C, G.A.; Baisie, M.; Baraloto, C.; Camargo, P.B.; Barroso, J.; Blanc, L.; Bonal, D.; Bongers, F.; Boot, R.; Brown, F.; Burban, B.; Camargo, J.L.; Castro, W.; Moscoso, V.C.; Chave, J.; Comiskey, J.; Valverde, F.C.; da Costa, A.L.; Cardozo, N.D.; Di Fiore, A.; Dourdain, A.; Erwin, T.; Llampazo, G.F.; Vieira, I.C.G.; Herrera, R.; Honorio Coronado, E.; Huamantupa-Chuquimaco, I.; Jimenez-Rojas, E.; Killeen, T.; Laurance, S.; Laurance, W.; Levesley, A.; Lewis, S.L.; Ladvocat, K.L.L.M.; Lopez-Gonzalez, G.; Lovejoy, T.; Meir, P.; Mendoza, C.; Morandi, P.; Neill, D.; Nogueira Lima, A.J.; Vargas, P.N.; de Oliveira, E.A.; Camacho, N.P.; Pardo, G.; Peacock, J.; Peña-Claros, M.; Peñuela-Mora, M.C.; Pickavance, G.; Pipoly, J.; Pitman, N.; Prieto, A.; Pugh, T.A.M.; Quesada, C.; Ramirez-Angulo, H.; de Almeida Reis, S.M.; Rejou-Machain, M.; Correa, Z.R.; Bayona, L.R.; Rudas, A.; Salomão, R.; Serrano, J.; Espejo, J.S.; Silva, N.; Singh, J.; Stahl, C.; Stropp, J.; Swamy, V.; Talbot, J.; ter Steege, H.; Terborgh, J.; Thomas, R.; Toledo, M.; Torres-Lezama, A.; Gamarra, L.V.; van der Heijden, G.; van der Meer, P.; van der Hout, P.; Martinez, R.V.; Vieira, S.A.; Cayo, J.V.; Vos, V.; Zagt, R.; Zuidema, P.; Galbraith, D. doi  openurl
  Title Tree mode of death and mortality risk factors across Amazon forests Type Journal Article
  Year 2020 Publication Nature Communications Abbreviated Journal Nat. Commun.  
  Volume (up) 11 Issue 5515 Pages  
  Keywords bioclimatology; carbon sink; ecological modeling; growth; holistic approach; mortality; mortality risk; risk factor; survival; trade-off; tropical forest; article; climate; controlled study; forest; growth rate; human; mortality rate; mortality risk; survival; biological model; biomass; Brazil; carbon sequestration; ecology; ecosystem; environmental monitoring; growth, development and aging; proportional hazards model; risk factor; tree; tropic climate; Amazonia; carbon dioxide; Biomass; Brazil; Carbon Dioxide; Carbon Sequestration; Ecology; Ecosystem; Environmental Monitoring; Forests; Models, Biological; Proportional Hazards Models; Risk Factors; Trees; Tropical Climate  
  Abstract The carbon sink capacity of tropical forests is substantially affected by tree mortality. However, the main drivers of tropical tree death remain largely unknown. Here we present a pan-Amazonian assessment of how and why trees die, analysing over 120,000 trees representing > 3800 species from 189 long-term RAINFOR forest plots. While tree mortality rates vary greatly Amazon-wide, on average trees are as likely to die standing as they are broken or uprooted—modes of death with different ecological consequences. Species-level growth rate is the single most important predictor of tree death in Amazonia, with faster-growing species being at higher risk. Within species, however, the slowest-growing trees are at greatest risk while the effect of tree size varies across the basin. In the driest Amazonian region species-level bioclimatic distributional patterns also predict the risk of death, suggesting that these forests are experiencing climatic conditions beyond their adaptative limits. These results provide not only a holistic pan-Amazonian picture of tree death but large-scale evidence for the overarching importance of the growth–survival trade-off in driving tropical tree mortality. © 2020, The Author(s).  
  Address Tropenbos International, Wageningen, Netherlands  
  Corporate Author Thesis  
  Publisher Nature Research Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 20411723 (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 945  
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Author Thomas, H.J.D.; Bjorkman, A.D.; Myers-Smith, I.H.; Elmendorf, S.C.; Kattge, J.; Diaz, S.; Vellend, M.; Blok, D.; Cornelissen, J.H.C.; Forbes, B.C.; Henry, G.H.R.; Hollister, R.D.; Normand, S.; Prevéy, J.S.; Rixen, C.; Schaepman-Strub, G.; Wilmking, M.; Wipf, S.; Cornwell, W.K.; Beck, P.S.A.; Georges, D.; Goetz, S.J.; Guay, K.C.; Rüger, N.; Soudzilovskaia, N.A.; Spasojevic, M.J.; Alatalo, J.M.; Alexander, H.D.; Anadon-Rosell, A.; Angers-Blondin, S.; te Beest, M.; Berner, L.T.; Björk, R.G.; Buchwal, A.; Buras, A.; Carbognani, M.; Christie, K.S.; Collier, L.S.; Cooper, E.J.; Elberling, B.; Eskelinen, A.; Frei, E.R.; Grau, O.; Grogan, P.; Hallinger, M.; Heijmans, M.M.P.D.; Hermanutz, L.; Hudson, J.M.G.; Johnstone, J.F.; Hülber, K.; Iturrate-Garcia, M.; Iversen, C.M.; Jaroszynska, F.; Kaarlejarvi, E.; Kulonen, A.; Lamarque, L.J.; Lantz, T.C.; Lévesque, E.; Little, C.J.; Michelsen, A.; Milbau, A.; Nabe-Nielsen, J.; Nielsen, S.S.; Ninot, J.M.; Oberbauer, S.F.; Olofsson, J.; Onipchenko, V.G.; Petraglia, A.; Rumpf, S.B.; Shetti, R.; Speed, J.D.M.; Suding, K.N.; Tape, K.D.; Tomaselli, M.; Trant, A.J.; Treier, U.A.; Tremblay, M.; Venn, S.E.; Vowles, T.; Weijers, S.; Wookey, P.A.; Zamin, T.J.; Bahn, M.; Blonder, B.; van Bodegom, P.M.; Bond-Lamberty, B.; Campetella, G.; Cerabolini, B.E.L.; Chapin, F.S., III; Craine, J.M.; Dainese, M.; Green, W.A.; Jansen, S.; Kleyer, M.; Manning, P.; Niinemets, Ü.; Onoda, Y.; Ozinga, W.A.; Peñuelas, J.; Poschlod, P.; Reich, P.B.; Sandel, B.; Schamp, B.S.; Sheremetiev, S.N.; de Vries, F.T. doi  openurl
  Title Global plant trait relationships extend to the climatic extremes of the tundra biome Type Journal Article
  Year 2020 Publication Nature Communications Abbreviated Journal Nat. Commun.  
  Volume (up) 11 Issue 1351 Pages  
  Keywords biome; climate change; extreme event; global change; growth; interspecific interaction; plant community; tundra; article; plant community; prediction; tundra; warming; classification; climate; ecosystem; genetics; plant; plant development; Climate; Ecosystem; Plant Development; Plants; Tundra  
  Abstract The majority of variation in six traits critical to the growth, survival and reproduction of plant species is thought to be organised along just two dimensions, corresponding to strategies of plant size and resource acquisition. However, it is unknown whether global plant trait relationships extend to climatic extremes, and if these interspecific relationships are confounded by trait variation within species. We test whether trait relationships extend to the cold extremes of life on Earth using the largest database of tundra plant traits yet compiled. We show that tundra plants demonstrate remarkably similar resource economic traits, but not size traits, compared to global distributions, and exhibit the same two dimensions of trait variation. Three quarters of trait variation occurs among species, mirroring global estimates of interspecific trait variation. Plant trait relationships are thus generalizable to the edge of global trait-space, informing prediction of plant community change in a warming world. © 2020, Crown.  
  Address Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Postbus 94240, Amsterdam, 1090 GE, Netherlands  
  Corporate Author Thesis  
  Publisher Nature Research Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 20411723 (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 947  
Permanent link to this record
 

 
Author Ziegler, C.; Dusenge, M.E.; Nyirambangutse, B.; Zibera, E.; Wallin, G.; Uddling, J. doi  openurl
  Title Contrasting Dependencies of Photosynthetic Capacity on Leaf Nitrogen in Early- and Late-Successional Tropical Montane Tree Species Type Journal Article
  Year 2020 Publication Frontiers in Plant Science Abbreviated Journal Front. Plant Sci.  
  Volume (up) 11 Issue Pages 500479  
  Keywords allocation; early successional; late successional; nitrogen; photosynthesis; tropical montane forests  
  Abstract Differences in photosynthetic capacity among tree species and tree functional types are currently assumed to be largely driven by variation in leaf nutrient content, particularly nitrogen (N). However, recent studies indicate that leaf N content is often a poor predictor of variation in photosynthetic capacity in tropical trees. In this study, we explored the relative importance of area-based total leaf N content (Ntot) and within-leaf N allocation to photosynthetic capacity versus light-harvesting in controlling the variation in photosynthetic capacity (i.e. Vcmax, Jmax) among mature trees of 12 species belonging to either early (ES) or late successional (LS) groups growing in a tropical montane rainforest in Rwanda, Central Africa. Photosynthetic capacity at a common leaf temperature of 25˚C (i.e. maximum rates of Rubisco carboxylation, Vcmax25 and of electron transport, Jmax25) was higher in ES than in LS species (+ 58% and 68% for Vcmax25 and Jmax25, respectively). While Ntot did not significantly differ between successional groups, the photosynthetic dependency on Ntot was markedly different. In ES species, Vcmax25 was strongly and positively related to Ntot but this was not the case in LS species. However, there was no significant trade-off between relative leaf N investments in compounds maximizing photosynthetic capacity versus compounds maximizing light harvesting. Both leaf dark respiration at 25˚C (+ 33%) and, more surprisingly, apparent photosynthetic quantum yield (+ 35%) was higher in ES than in LS species. Moreover, Rd25 was positively related to Ntot for both ES and LS species. Our results imply that efforts to quantify carbon fluxes of tropical montane rainforests would be improved if they considered contrasting within-leaf N allocation and photosynthetic Ntot dependencies between species with different successional strategies. © Copyright © 2020 Ziegler, Dusenge, Nyirambangutse, Zibera, Wallin and Uddling.  
  Address Department of Biology, The University of Western Ontario, London, ON, Canada  
  Corporate Author Thesis  
  Publisher Frontiers Media S.A. Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1664462x (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 953  
Permanent link to this record
 

 
Author Gargallo-Garriga, Albert ; Sardans, Jordi ; Alrefaei, Abdulwahed Fahad ; Klem, Karel ; Fuchslueger, Lucia ; Ramirez-Rojas, Irène ; Donald, Julian ; Leroy, Celine ; Van Langenhove, Leandro ; Verbruggen, Erik ; Janssens, Ivan A. ; Urban, Otmar ; Penuelas, Josep doi  openurl
  Title Tree Species and Epiphyte Taxa Determine the “Metabolomic niche” of Canopy Suspended Soils in a Species-Rich Lowland Tropical Rainforest Type Journal Article
  Year 2021 Publication Metabolites Abbreviated Journal  
  Volume (up) 11 Issue 11 Pages  
  Keywords Bacteria, Canopy soils, Epiphyte, French Guiana, Metabolomics  
  Abstract Tropical forests are biodiversity hotspots, but it is not well understood how this diversity is structured and maintained. One hypothesis rests on the generation of a range of metabolic niches, with varied composition, supporting a high species diversity. Characterizing soil metabolomes can reveal fine-scale differences in composition and potentially help explain variation across these habitats. In particular, little is known about canopy soils, which are unique habitats that are likely to be sources of additional biodiversity and biogeochemical cycling in tropical forests. We studied the effects of diverse tree species and epiphytes on soil metabolomic profiles of forest floor and canopy suspended soils in a French Guianese rainforest. We found that the metabolomic profiles of canopy suspended soils were distinct from those of forest floor soils, differing between epiphyte-associated and non-epiphyte suspended soils, and the metabolomic profiles of suspended soils varied with host tree species, regardless of association with epiphyte. Thus, tree species is a key driver of rainforest suspended soil metabolomics. We found greater abundance of metabolites in suspended soils, particularly in groups associated with plants, such as phenolic compounds, and with metabolic pathways related to amino acids, nucleotides, and energy metabolism, due to the greater relative proportion of tree and epiphyte organic material derived from litter and root exudates, indicating a strong legacy of parent biological material. Our study provides evidence for the role of tree and epiphyte species in canopy soil metabolomic composition and in maintaining the high levels of soil metabolome diversity in this tropical rainforest. It is likely that a wide array of canopy microsite-level environmental conditions, which reflect interactions between trees and epiphytes, increase the microscale diversity in suspended soil metabolomes  
  Address  
  Corporate Author Thesis  
  Publisher MDPI Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 1041  
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Author Urbina, Ifigenia ; Grau, Oriol ; Sardans, Jordi ; Margalef, Olga ; Peguero, Guillermo ; Asensio, Dolores ; Llusia, Joan ; Ogaya, Roma ; Gargallo-Garriga, Albert ; Van Langenhove, Leandro ; Verryckt, Lore T. ; Courtois, Elodie A. ; Stahl, Clement ; Soong, Jennifer L. ; Chave, Jérome ; Hérault, Bruno ; Janssens, Ivan A. ; Sayer, Emma ; Penuelas, Josep doi  openurl
  Title High foliar K and P resorption efficiencies in old-growth tropical forests growing on nutrient-poor soils Type Journal Article
  Year 2021 Publication Ecology and Evolution Abbreviated Journal  
  Volume (up) 11 Issue 13 Pages 8969-8982  
  Keywords  
  Abstract Resorption is the active withdrawal of nutrients before leaf abscission. This mechanism represents an important strategy to maintain efficient nutrient cycling; however, resorption is poorly characterized in old-growth tropical forests growing in nutrient-poor soils. We investigated nutrient resorption from leaves in 39 tree species in two tropical forests on the Guiana Shield, French Guiana, to investigate whether resorption efficiencies varied with soil nutrient, seasonality, and species traits. The stocks of P in leaves, litter, and soil were low at both sites, indicating potential P limitation of the forests. Accordingly, mean resorption efficiencies were higher for P (35.9%) and potassium (K; 44.6%) than for nitrogen (N; 10.3%). K resorption was higher in the wet (70.2%) than in the dry (41.7%) season. P resorption increased slightly with decreasing total soil P; and N and P resorptions were positively related to their foliar concentrations. We conclude that nutrient resorption is a key plant nutrition strategy in these old-growth tropical forests, that trees with high foliar nutrient concentration reabsorb more nutrient, and that nutrients resorption in leaves, except P, are quite decoupled from nutrients in the soil. Seasonality and biochemical limitation played a role in the resorption of nutrients in leaves, but species-specific requirements obscured general tendencies at stand and ecosystem level.  
  Address  
  Corporate Author Thesis  
  Publisher Wiley Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 1011  
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Author Barriault, I.; Barabe, D.; Cloutier, L.; Gibernau, M. openurl 
  Title Pollination ecology and reproductive success in Jack-in-the-pulpit (Arisaema triphyllum) in Quebec (Canada) Type Journal Article
  Year 2010 Publication Plant Biology Abbreviated Journal Plant Biol.  
  Volume (up) 12 Issue 1 Pages 161-171  
  Keywords Araceae; bisexual inflorescence; deceptive pollination; Mycetophilidae; pollen load; Thysanoptera; visitation rates  
  Abstract Pollination ecology and reproductive success of Jack-in-the-pulpit (Arisaema triphyllum) were studied in two natural populations in Quebec, Canada. Individual A. triphyllum plants can be of three types: male, female or bisexual. In both populations studied, the presence of bisexual inflorescences was not negligible (13%), where 'female' and 'male' bisexual plants were categorised according to the relative number of stamens and ovaries. 'Male bisexual' plants produce only pollen and 'female bisexual' plants produce only fruit. Hence, A. triphyllum is a true dioecious plant, as each plant only reproduces through either the male or the female function. 'Female bisexual' plants were equivalent to female plants in terms of visitation rate by insects, fructification rate and production of berries and seeds. Neither agamospermy in female plants nor self-pollination in 'female bisexual' plants was found, thus A. triphyllum relies on insects for cross-pollination. Despite the long flowering cycle, a low visitation rate was documented: only 20-40% of inflorescences were visited, according to gender, by a mean of 1.5 insects. In this study, Mycetophilidae represented the most generically diversified and abundant family, as well as the most efficient insect pollinator, especially the genera Docosia and Mycetophila.  
  Address [Gibernau, M.] Univ Toulouse 3, Lab Evolut & Divers Biol, UMR, CNRS, F-31062 Toulouse 9, France, Email: gibernau@cict.fr  
  Corporate Author Thesis  
  Publisher WILEY-BLACKWELL PUBLISHING, INC Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1435-8603 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000272589700017 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 89  
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Author Kenne, M.; Feneron, R.; Djieto-Lordon, C.; Malherbe, M.C.; Tindo, M.; Ngnegueu, P.R.; Dejean, A. openurl 
  Title Nesting and foraging habits in the arboreal ant Atopomyrmex mocquerysi ANDRE, 1889 (Hymenoptera: Formicidae: Myrmicinae) Type Journal Article
  Year 2009 Publication Myrmecological News Abbreviated Journal Myrmecol. News  
  Volume (up) 12 Issue Pages 109-115  
  Keywords Cameroon; wood-excavating ant; nest site selection; pest ant; predatory behavior; rhythm of activity; life history  
  Abstract Atopomyrmex mocquerysi ANDRE, 1889 is a West-Central African wood-excavating myrmicine species whose colonies construct galleries in the main live branches of their host trees, causing the distal parts of these branches to dry out. In southeastern Cameroon, this species was mainly found in woody savannahs that are burned annually. It was also present in the canopy of a secondary forest, but was relatively rare on trees growing along forest edges and entirely absent from the canopy of an old-growth forest. It was absent from oil palm and coffee tree plantations, rare on cocoa trees. present on 0.2% to 5.3% of the avocado, guava, mango and Citrus spp. trees monitored, and frequent on safoo trees (12.4%). A fire in a mango plantation seems to have favored its presence. The colonies generally exploit Aleyrodidae, Aphididae, Coccidae, and Stictococcidae. Workers forage for prey diurnally, mostly on the ground. Their predatory behavior is characterized by detection through contact. Workers recruit nestmates at short-range (within range of an alarm pheromone), rarely at long-range, after which they spread-eagle the prey and immediately cut it up on the spot. Individual workers retrieve the prey pieces. Unlike other territorially-dominant arboreal ants, A. mocquerysi is a threat to host trees because. in addition to being a wood-excavating species, its workers only slightly protect the foliage of their host tree from herbivorous insects since they mostly hunt on the ground.  
  Address [Kenne, Martin; Tindo, Maurice] Univ Douala, Fac Sci, Dept Biol Organismes Anim, Douala, Cameroon, Email: medoum68@yahoo.fr  
  Corporate Author Thesis  
  Publisher OESTERREICHISCHE GESELL ENTOMOFAUNISTIK, C/O NATURHISTOR MUSEUM WIEN Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1994-4136 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000271357700012 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 97  
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Author Szilagyi, A.; Scheuring, I.; Edwards, D.P.; Orivel, J.; Yu, D.W. openurl 
  Title The evolution of intermediate castration virulence and ant coexistence in a spatially structured environment Type Journal Article
  Year 2009 Publication Ecology Letters Abbreviated Journal Ecol. Lett.  
  Volume (up) 12 Issue 12 Pages 1306-1316  
  Keywords Cooperation; evolution of virulence; host-pathogen; mutualism; myrmecophyte; parasite; rock-paper-scissors; spatial games; tolerance; trade-off  
  Abstract Theory suggests that spatial structuring should select for intermediate levels of virulence in parasites, but empirical tests are rare and have never been conducted with castration (sterilizing) parasites. To test this theory in a natural landscape, we construct a spatially explicit model of the symbiosis between the ant-plant Cordia nodosa and its two, protecting ant symbionts, Allomerus and Azteca. Allomerus is also a castration parasite, preventing fruiting to increase colony fecundity. Limiting the dispersal of Allomerus and host plant selects for intermediate castration virulence. Increasing the frequency of the mutualist, Azteca, selects for higher castration virulence in Allomerus, because seeds from Azteca-inhabited plants are a public good that Allomerus exploits. These results are consistent with field observations and, to our knowledge, provide the first empirical evidence supporting the hypothesis that spatial structure can reduce castration virulence and the first such evidence in a natural landscape for either mortality or castration virulence.  
  Address [Edwards, David P.; Yu, Douglas W.] Univ E Anglia, Sch Biol Sci, Norwich NR4 7TJ, Norfolk, England, Email: dougwyu@gmail.com  
  Corporate Author Thesis  
  Publisher WILEY-BLACKWELL PUBLISHING, INC Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1461-023X ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000271631500006 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 192  
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Author Ponton, S.; Flanagan, L.B.; Alstad, K.P.; Johnson, B.G.; Morgenstern, K.; Kljun, N.; Black, T.A.; Barr, A.G. openurl 
  Title Comparison of ecosystem water-use efficiency among Douglas-fir forest, aspen forest and grassland using eddy covariance and carbon isotope techniques Type Journal Article
  Year 2006 Publication Global Change Biology Abbreviated Journal Glob. Change Biol.  
  Volume (up) 12 Issue 2 Pages 294-310  
  Keywords boreal forest; conifer forest; eddy covariance; grassland; stable isotopes  
  Abstract Comparisons were made among Douglas-fir forest, aspen (broad leaf deciduous) forest and wheatgrass (C-3) grassland for ecosystem-level water-use efficiency (WUE). WUE was defined as the ratio of photosynthetic CO2 assimilation rate and evapotranspiration (ET) rate. The ET data measured by eddy covariance were screened so that they overwhelmingly represented transpiration. The three sites used in this comparison spanned a range of vegetation (plant functional) types and environmental conditions within western Canada. When compared in the relative order Douglas-fir (located on Vancouver Island, BC), aspen (northern Saskatchewan), grassland (southern Alberta), the sites demonstrated a progressive decline in precipitation and a general increase in maximum air temperature and atmospheric saturation deficit (D-max) during the mid-summer. The average (+/- SD) WUE at the grassland site was 2.6 +/- 0.7 mmol mol(-1), which was much lower than the average values observed for the two other sites (aspen: 5.4 +/- 2.3, Douglas-fir: 8.1 +/- 2.4). The differences in WUE among sites were primarily because of variation in ET. The highest maximum ET rates were approximately 5, 3.2 and 2.7 mm day(-1) for the grassland, aspen and Douglas-fir sites, respectively. There was a strong negative correlation between WUE and D-max for all sites. We also made seasonal measurements of the carbon isotope ratio of ecosystem respired CO2 (delta(R)) in order to test for the expected correlation between shifts in environmental conditions and changes to the ecosystem-integrated ratio of leaf intercellular to ambient CO2 concentration (c(i)/c(a)). There was a consistent increase in delta(R) values in the grassland, aspen forest and Douglas-fir forest associated with a seasonal reduction in soil moisture. Comparisons were made between WUE measured using eddy covariance with that calculated based on D and delta(R) measurements. There was excellent agreement between WUE values calculated using the two techniques. Our delta(R) measurements indicated that c(i)/c(a) values were quite similar among the Douglas-fir, aspen and grassland sites, despite large variation in environmental conditions among sites. This implied that the shorter-lived grass species had relatively high c(i)/c(a) values for the D of their habitat. By contrast, the longer-lived Douglas-fir trees were more conservative in water-use with lower c(i)/c(a) values relative to their habitat D. This illustrates the interaction between biological and environmental characteristics influencing ecosystem-level WUE. The strong correlation we observed between the two independent measurements of WUE, indicates that the stable isotope composition of respired CO2 is a useful ecosystem-scale tool to help study constraints to photosynthesis and acclimation of ecosystems to environmental stress.  
  Address Univ Lethbridge, Dept Biol Sci, Lethbridge, AB T1K 3M4, Canada, Email: larry.flanagan@uleth.ca  
  Corporate Author Thesis  
  Publisher BLACKWELL PUBLISHING Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1354-1013 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000234974900013 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 226  
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Author Charles-Dominique, P.; Chave, J.; Dubois, M.A.; De Granville, J.J.; Riera, B.; Vezzoli, C. openurl 
  Title Colonization front of the understorey palm Astrocaryum sciophilum in a pristine rain forest of French Guiana Type Journal Article
  Year 2003 Publication Global Ecology and Biogeography Abbreviated Journal Glob. Ecol. Biogeogr.  
  Volume (up) 12 Issue 3 Pages 237-248  
  Keywords Astrocaryum sciophilum; French Guiana; neotropical palaeoecology; palm ecology; population edge; refuges; scatter-hoarding; seed dispersal; spatial pattern  
  Abstract Aims Astrocaryum sciophilum (Miq.) Pulle (Arecaceae) is an understorey palm, endemic to north-eastern South America with a patchy distribution. We tested the hypothesis that the spatial distribution of this palm species is not in equilibrium but is slowly colonizing the forest understorey. Location Inventories and seed dispersal studies were conducted in the undisturbed tropical forest close to the Nouragues research station, French Guiana. Additional data were collected in the entire territory of French Guiana. Methods We studied the demography of A. sciophilum on a 20-ha plot located at the edge of its distribution. The age of the palms was estimated by postulating an exponentially decreasing abundance by age class. Direct seed dispersal experiments were also conducted, to estimate dispersal parameters. The seeds of A. sciophilum were dispersed only by rodents. This information was used to parameterize a forest growth simulator, to study the spatial spread of this species. Results Within the sampling plot, the density of A. sciophilum dropped sharply from about 500 individuals per hectare to zero. The maturation age was estimated to be 170+/-70 years, and over 55 years with 95% confidence. Seed-dispersal experiments yielded an average seed dispersal distance of 11 m and a maximum estimated dispersal distance of 125 m across a generational span of 55 years to maturity. Therefore, the maximal estimated colonization speed is 2.3 m/y. Conclusions Empirical results and numerical simulations suggest that the boundary of the A. sciophilum population is a colonization front, and that the range of this species is slowly expanding. The implications of this result in respect of palaeoenvironmental changes in this region are discussed.  
  Address Natl Museum Nat Hist, Lab Ecol Gen, F-91800 Brunoy, France  
  Corporate Author Thesis  
  Publisher BLACKWELL PUBLISHING LTD Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0960-7447 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000182184100006 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 273  
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